Vascular diseases are among the commonest disorders having a fatal outcome. Warranting particular mention is myocardial infarction due to diseased coronary vessels. Arteriosclerotic plaque results in more or less severe blocking of the coronary vessels.
Various methods have been developed in recent years for treating such cases of narrowing of, for example, coronary vessels or other parts of the vascular system. Such treatment attempts to clear the plaque away or, as the case may be, destroy it and/or to dilate the vessel in order thereby to remove the vascular occlusion. Interventions of said type for treating a partial or total vascular occlusion are mostly performed under x-ray control using an angiography system, although the vessels concerned such as, for example, the coronary vessels will then be shown only two-dimensionally in silhouette form. To render the vessel clearly visible it is additionally necessary to inject a contrast medium into the vessels, although that will not be able to reach all areas of the vessels in the case of a total occlusion. An associated problem is that many patients are allergic to contrast media or will develop a heat sensation due to the contrast medium. Moreover, patients may also sustain radiation injuries.
For the medical personnel, on the other hand, it is difficult to distinguish between the plaque and vessel wall during the intervention owing to the very limited imaging even when a contrast medium is applied. That increases the risk of clearing away or, as the case may be, destroying tissue at wrong places so that, for example, damage may occur to the vessel wall.
Where attempts have been made to resolve such problems by supplementing x-ray monitoring with additional image monitoring, the problem remains that, depending on the specific type of additional image monitoring employed, it is possible to achieve only a limited spatial resolution or, as the case may be, a good resolution only in the close range, but not a representation that is satisfactory overall.
The cutting balloon is a special balloon bearing three or four small knives depending on its size. These stand up when the balloon opens out and make longitudinal cuts in the vessel's deposits or, as the case may be, “shave” plaque away from the vessel wall before the coronary artery is dilated by the balloon.
The aim of this technique is to reduce or even eliminate the elastic restoring forces in order thereby to achieve a greater diameter of the vessel following dilation. Irregular tears in the vascular endothelium that can be responsible for acute occlusions following ballooning will furthermore be avoided. Studies have shown that hyperplasia (inflammatory reaction with swelling) of the vascular endothelium following balloon dilatation can also be reduced and hence that the restenosing rate can be significantly reduced through using the cutting balloon.
A device functioning on the cutting-balloon principle is described in, for example, WO 82/04388 A1, “Coronary Cutting and Dilating Instrument”, and in WO 02/078511 A2, “Inflatable Medical Device with Combination Cutting Elements and Drug Delivery Conduits”. What is known as a product is the Cutting Balloon Ultra, for example, made by Boston Scientific, MA, USA; products are also available from Interventional Technologies, San Diego, Calif., USA.
A device for performing a cutting-balloon intervention with OCT monitoring is proposed in U.S. 2005/0222594 A1; a similar device with IVUS monitoring is known from U.S. 2005/0222596 A1.
To keep the vessel open it is often necessary in the treatment of vascular diseases to insert a stent, which is a vessel support that mechanically stabilizes the vessel wall. The use of stents allows the vessel to be further dilated, for example. To insert such stents it has hitherto been necessary first to remove the catheter on which the therapy implement for treating the vasoconstriction is provided then insert the stent using a second catheter. That, though, is a procedure that puts a strain on the patient and entails risks, particularly in terms of restenosing.